Cerebral Activation Patterns in the Preparation and Movement Periods of Spontaneous and Evoked Movements

Many BMI (brain machine interface) researches on the control of a prosthetic upper-limb/hand have been conducted. However, the BMI researches on the control of a walking-assistive device were few. Otherwise, brain activation was usually measured in a synchronous control mode. This reduced the naturality of brain activation. To realize asynchronous BMI control of a walking-assistive device, this paper studied cerebral activation pattern in both the spontaneous (asynchronous) and evoked (synchronous) movement states. Stepping and squatting stances movements were performed. Cerebral activation was simultaneously measured using NIRS (near-infrared spectroscopy) technology. Analysis of variation revealed that cerebral activation patterns in the two motion modes had a significant difference in both the imaginary/ preparation periods and movement periods. Particularly, the spontaneous movement achieved a more distinct difference than the evoked movement. It is confirmed that cerebral activation in the preparation periods of spontaneous movement is preferable for identifying motion intention of lower limbs.